#include <stdio.h>

int sum(int n){
  int i =1;
  int sum = 0;
  for(;i<=n;i++){
    sum+=i;
  }
  return sum;
}

int main(){
  printf("\n");
  printf("--------------------------------------------\n");
  printf("开始执行\n");
  int result = sum(100);
  printf("result is %d\n",result);
  printf("--------------------------------------------\n");
  printf("\n");
  return 0;
}
